These kinds of debates most commonly devolve (on the part of the crackpots) to naked assertions about epistemological presuppositions and method, as there's really no way they can directly engage the scientific evidence in a manner that at all approximates adequateness. Nye must be angling for some PR capital, because the debate is going to produce far more frustration and misinformation than actual education as a result of Nye's having to waste a lot of time fielding Ham's nonsense.